Effect of helium partial pressure on DC-magnetron sputtering of Co-Cr films

The effect of diluting the argon sputter gas with helium in DC-magnetron sp uttering of both CoCr magnetic layers and Cr underlayers was studied. A Co8 8Cr12 target and a PET substrate were used. The addition of helium markedly improved the longitudinal magnetic properties and the magnetic uniformity of the films. It is shown that sputtering of the Cr underlayer with a He/Ar mixture improved the magnetic properties of the CoCr film which was sputte red subsequently; an explanation is that the structure of the Cr him sputte red with He/Ar is better suited to the epitaxial growth of CoCr. The benefi cial effects of He are ascribed to an increased ion bombardment on the subs trate. This is supported by measurement of the ion current of the substrate and by SEM measurements. (C) 1999 Elsevier Science B.V. All rights reserve d.